Time delay fuze



April M ECHANICAL G. L. WEST ET AL TIME DELAY FUZE 2 Sheets-Sheet 1 TIMER OUT-OF-LINE P I l L i P l L ANTIDISTURBANCE AOTUATION TIMER ACTUATION FIG. 3.

SWITCH T 24\* 32 DETONATOR l FIG. I.

FIG. 2.

31 F 29 Hi: 7S

24 25 28 lie-"1 v 4- fif' j r-h -w NC no] I I ls I s, II I L J L J I l l INVENTORS.

GAYLON L. WEST ROBERT H. FORSTER DONALD G. QUIST ROBERT L. CLAPP ROY MILLER ATTORNEY.

April 7, 1970 w s ET AL TIME DELAY FUZE' 2 Sheets-Sheet 2 Filed June 4, 1968 FIG. 4.

United States Patent 3,504,632 TIME DELAY FUZE Gaylon L. West, Robert H. Forster, Donald G. Quist, and

Robert L. Clapp, China Lake, Califl, assignors to the United States of America as represented by the Secretary of the Navy Filed June 4, 1968, Ser. No. 734,843 Int. .Cl. F42c 9/02 US. Cl. 10270.2 6 Claims ABSTRACT OF THE DISCLOSURE A fuze having a mechanical safety, a mechanical arming delay timer, an electronic arming timer, an anidisturbance firing mechanism, and a second electronic timer to detonate the fuze after a prescribed period of time if the anti-disturbance firing mechanism is not activated.

GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties therein or therefor.

BACKGROUND OF THE INVENTION SUMMARY OF THE INVENTION In accordance with the present invention, a mechanical timer in the form of a runaway escapement clock mechanism is initiated. After the timer completes its cycle, a mechanical arm slides into position to permit detonation.

At the same time the mechanical timer is initiated, first and second electronic timers begin their cycles. The time constant of the first electronic timer is chosen so that the first electronic timer will complete its cycle shortly after the mechanical timer cycles.

The first electronic timer fully arms the fuze, and detonation will occur in response to the movement of a trembler switch.

The time constant of the second electronic timer is chosen so that it will complete its cycle considerably after the first electronic timer arms the fuze. When the second electronic timer cycles, detonation will occur.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a block diagram of the system;

FIG. 2 is a time-line of operation of the system shown in FIG. 1;

FIG. 3 is a schematic diagram of the electronic circuitry of the system of FIG. 1; and

FIG. 4 is a plan view of the mechanical timer of the system of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a mechanical timer 23, which may be of the type shown in FIG. 4 begins its timing cycle at time t as shown in FIG. 2. After timer 23 completes its cycle at time t a mechanical arm slides into position lining up two holes 21 and 21 shown in FIG. 4. Out-ofline switch 32, which comprises holes 21 and 21 of FIG. 4 will prevent detonation when closed, and enable detonation when open.

Electrical circuitry 26 is initiated simultaneously with mechanical timer 23. A first electrical timer 25, which may be an E cell as shown in FIG. 3, initiates at time t and completes its cycle at time t When electrical timer 25 completes its cycle, the fuze is armed to enable detonation by anti-disturbance actuation means 27 or by a second electrical timing means 28. Anti-disturbance actuation means 27 may be a trembler switch as shown in FIG. 3, and second electrical timer actuation 28 may be a second B cell 28, shown in FIG. 3.

Timer actuation 28 is set to detonate the fuze via detonator 24 at a prescribed time, t after time t If the fuze is disturbed during the time interval from t until t the anti-disturbance actuation means 27 will detonate the fuze via detonator 24 at time 1 FIG. 4 shows a plan view of timer 23. The timer controls an out-of-line rotor 17 and microswitch 18 (which is comprised of S and S The once-and-done timer 23 is actuated by depressing push button plunger 10. As plunger 10 is depressed, a rack 11 engages a main shaft and winds a mainspring (not shown). On reaching; the depressed position a detent 20 snaps into a hole 30 in plunger 10. The plunger is held in position thus giving a visual indication of the timer status. Prior to depressing plunger 10, grommet 14 and safety pin 13 are removed.

The plunger engages a runaway escapement start spring at the bottom of its stroke. Simultaneously, actuator 15 closes switches S and S of microswitch 18. As the escapement mechanism runs down, D- shaft 12 rotates to allow spring loaded rotor 17 to snap past it into the armed position. Spring loaded rotor 17 stops travel in response to rotor stop 16 which insures that out-of-line hole 21 will be in line with hole 21'.

The D shaft will permit arming at time t as shown in FIG. 2. Priming material is fastened to primer well 19 at hole 21', and booster material is placed near hole 21. Thus, when rotor 17 is out-of-line, if the primer in primer well 19 at hole 21' were to fire accidentally, the booster material at hole 21 would not fire to cause detonation.

Referring to the electrical circuit 26 shown in FIG. 3, switches S and S shift from the normally closed (NC) position to the normally open (NO) position at time t In the normally closed position, S disconnects a voltage source V and shorts the circuit to prevent accidental firing. Switch S in the normally closed position shorts out detonation 24 to further prevent accidental firing. If silicon controlled rectifier 29 were defective, resistor 33 would limit the current flowing to detonator 24, to prevent accidental firing when the plunger is depressed at time t When switches S and S shift positions at time t a potential is placed across a first E cell 25, and a second E cell 28. An E cell has the property that a low (around .1 volt) potential will remain across it until, after a predetermined time current interval, the E cell breaks down and the potential across it rises (to about .9 volt). This characteristic is exhibited no matter what potential (up to a certain point) is placed across its terminals.

At time t .1 volt appears at point 34, and at time t the potential at point 34 rises to about .9 volt, thus enabling trembler switch 27 to fire silicon controlled rectifier 29 to place a potential across detonator 24 to set off a charge. Detonation by trembler actuation is represented in FIG. 2 as occurring at time t If detonation by trembler actuation does not occur, B cell 28 will rise in potential to .9 volt at time t and a current will pass through diode 31 to fire silicon controlled rectifier 29 which in turn causes detonator 24 to set off a charge.

What is claimed is:

1. A fuze comprising:

means to simultaneously initiate mechanical and electrical timing means;

mechanical timing means to delay arming of the fuze for a first interval of time; 7

a first electrical timing means to permit detonation after a second interval of time, which interval is longer than the first interval of time;

anti-disturbance means for detonating the fuze any time after the Second interval of time; and

a second electrical timing means to detonate the fuze after a third interval of time which interval is longer than said second interval of time.

2. The system of claim 1 wherein said mechanical timing means to delay arming comprises:

push button plunger means to simultaneously initiate a clock timer and electrical timing means;

runaway escapement means for clocking said first tim interval;

an out-of-line spring actuated rotor capable of shifting from a first unarmed position to a second armed poistion wherein the armed position permits a primer mounted on a pallet to fire through a hole in said rotor to activate a booster mounted adjacent to the hole in the rotor; and

D ring rotor release means to permit the out-of-line rotor to shift positions when the D ring, which is operatively connected to the runaway ,escapement movement, turns to the proper position.

3. The system of claim 2 wherein the first electrical timing means comprises:

4 a first E cell properly biased which short circuits after a preselected time interval to enable detonation to occur.

4. The system of claim 3 wherein the anti-disturbance means for detonating the fuze comprises:

a switch capable of firing a properly biased silicon controlled rectifier which will detonate the fuze,

5. The system of claim 4 wherein the anti-disturbance switch is a trembler switch which is responsive to movement.

6. The system of claim 5 wherein the second electrical timing means comprises:

a second E cell properly biased which short circuits after a preselected period of time to cause said properly biased silicon controlled rectifier to conduct and detonate said fuze.

References Cited UNITED STATES PATENTS 2,831,430 4/1958 Robertson et al 1027l 2,988,991 6/1961 Elmer 10216 3,000,313 9/1961 Lareau et a1 10270.2 3,078,801 2/1963 Rzewinski et al. lO2-19.2 X 3,098,448 7/1963 Gisser et a1. 1027D.2 3,143,964 8/1964 Young 102-16 3,175,489 3/1965 Reed 10270.2 3,384,017 5/1968 Lazarus et al 10219.2 X

VERLIN R. PENDEGRASS, Primary Examiner 

